Stake funds with confirmations for front-running protection of Beacon Deposits

contracts/contracts/mocks/MockDepositContract.sol

@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+import { IDepositContract } from "./../interfaces/IDepositContract.sol";
+
+contract MockDepositContract is IDepositContract {
+    uint256 deposit_count;
+
+    function deposit(
+        bytes calldata pubkey,
+        bytes calldata withdrawal_credentials,
+        bytes calldata signature,
+        bytes32 deposit_data_root
+    ) external payable override {
+        require(pubkey.length == 48, "DepositContract: invalid pubkey length");
+        require(
+            withdrawal_credentials.length == 32,
+            "DepositContract: invalid withdrawal_credentials length"
+        );
+        require(
+            signature.length == 96,
+            "DepositContract: invalid signature length"
+        );
+
+        // Check deposit amount
+        require(msg.value >= 1 ether, "DepositContract: deposit value too low");
+        require(
+            msg.value % 1 gwei == 0,
+            "DepositContract: deposit value not multiple of gwei"
+        );
+        uint256 deposit_amount = msg.value / 1 gwei;
+        require(
+            deposit_amount <= type(uint64).max,
+            "DepositContract: deposit value too high"
+        );
+
+        // Emit `DepositEvent` log
+        bytes memory amount = to_little_endian_64(uint64(deposit_amount));
+        emit DepositEvent(
+            pubkey,
+            withdrawal_credentials,
+            amount,
+            signature,
+            to_little_endian_64(uint64(deposit_count))
+        );
+        require(
+            deposit_data_root != 0,
+            "DepositContract: invalid deposit_data_root"
+        );
+    }
+
+    function get_deposit_root() external view override returns (bytes32) {
+        // just return some bytes32
+        return sha256(abi.encodePacked(deposit_count, bytes16(0)));
+    }
+
+    /// @notice Query the current deposit count.
+    /// @return The deposit count encoded as a little endian 64-bit number.
+    function get_deposit_count() external view override returns (bytes memory) {
+        return to_little_endian_64(uint64(deposit_count));
+    }
+
+    function to_little_endian_64(uint64 value)
+        internal
+        pure
+        returns (bytes memory ret)
+    {
+        ret = new bytes(8);
+        bytes8 bytesValue = bytes8(value);
+        // Byteswapping during copying to bytes.
+        ret[0] = bytesValue[7];
+        ret[1] = bytesValue[6];
+        ret[2] = bytesValue[5];
+        ret[3] = bytesValue[4];
+        ret[4] = bytesValue[3];
+        ret[5] = bytesValue[2];
+        ret[6] = bytesValue[1];
+        ret[7] = bytesValue[0];
+    }
+}

contracts/contracts/mocks/MockSSVNetwork.sol

@@ -1,6 +1,32 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.0;
 
+import { Cluster } from "./../interfaces/ISSVNetwork.sol";
+
 contract MockSSVNetwork {
-    constructor() {}
+    function registerValidator(
+        bytes calldata publicKey,
+        uint64[] calldata operatorIds,
+        bytes calldata sharesData,
+        uint256 amount,
+        Cluster memory cluster
+    ) external {}
+
+    function exitValidator(
+        bytes calldata publicKey,
+        uint64[] calldata operatorIds
+    ) external {}
+
+    function removeValidator(
+        bytes calldata publicKey,
+        uint64[] calldata operatorIds,
+        Cluster memory cluster
+    ) external {}
+
+    function deposit(
+        address clusterOwner,
+        uint64[] calldata operatorIds,
+        uint256 amount,
+        Cluster memory cluster
+    ) external {}
 }

contracts/contracts/strategies/NativeStaking/ValidatorRegistrator.sol

@@ -37,9 +37,15 @@ abstract contract ValidatorRegistrator is Governable, Pausable {
     uint256 public activeDepositedValidators;
     /// @notice State of the validators keccak256(pubKey) => state
     mapping(bytes32 => VALIDATOR_STATE) public validatorsStates;
-
+    /// @notice The account that is allowed to modify stakeETHThreshold and reset stakeETHTally
+    address public stakingMonitor;
+    /// @notice Amount of ETH that can be staked before staking on the contract is suspended
+    /// and the governor needs to approve further staking
+    uint256 public stakeETHThreshold;
+    /// @notice Amount of ETH that can has been staked since the last governor approval.
+    uint256 public stakeETHTally;
     // For future use
-    uint256[50] private __gap;
+    uint256[47] private __gap;
 
     enum VALIDATOR_STATE {
         REGISTERED, // validator is registered on the SSV network
@@ -49,10 +55,13 @@ abstract contract ValidatorRegistrator is Governable, Pausable {
     }
 
     event RegistratorChanged(address newAddress);
+    event StakingMonitorChanged(address newAddress);
     event ETHStaked(bytes pubkey, uint256 amount, bytes withdrawal_credentials);
     event SSVValidatorRegistered(bytes pubkey, uint64[] operatorIds);
     event SSVValidatorExitInitiated(bytes pubkey, uint64[] operatorIds);
     event SSVValidatorExitCompleted(bytes pubkey, uint64[] operatorIds);
+    event StakeETHThresholdChanged(uint256 amount);
+    event StakeETHTallyReset();
 
     /// @dev Throws if called by any account other than the Registrator
     modifier onlyRegistrator() {
@@ -63,6 +72,12 @@ abstract contract ValidatorRegistrator is Governable, Pausable {
         _;
     }
 
+    /// @dev Throws if called by any account other than the Staking monitor
+    modifier onlyStakingMonitor() {
+        require(msg.sender == stakingMonitor, "Caller is not the Monitor");
+        _;
+    }
+
     /// @dev Throws if called by any account other than the Strategist
     modifier onlyStrategist() {
         require(
@@ -94,6 +109,26 @@ abstract contract ValidatorRegistrator is Governable, Pausable {
         validatorRegistrator = _address;
     }
 
+    /// @notice Set the address of the staking monitor that is allowed to modify
+    /// stakeETHThreshold and reset stakeETHTally
+    function setStakingMonitor(address _address) external onlyGovernor {
+        emit StakingMonitorChanged(_address);
+        stakingMonitor = _address;
+    }
+
+    /// @notice Set the amount of ETH that can be staked before governor needs to a approve
+    /// further staking.
+    function setStakeETHThreshold(uint256 _amount) external onlyStakingMonitor {
+        emit StakeETHThresholdChanged(_amount);
+        stakeETHThreshold = _amount;
+    }
+
+    /// @notice Reset the stakeETHTally
+    function resetStakeETHTally() external onlyStakingMonitor {
+        emit StakeETHTallyReset();
+        stakeETHTally = 0;
+    }
+
     /// @notice Stakes WETH to the node validators
     /// @param validators A list of validator data needed to stake.
     /// The `ValidatorStakeData` struct contains the pubkey, signature and depositDataRoot.
@@ -112,6 +147,12 @@ abstract contract ValidatorRegistrator is Governable, Pausable {
             "insufficient WETH"
         );
 
+        require(
+            stakeETHTally + requiredETH <= stakeETHThreshold,
+            "Staking ETH over approved threshold"
+        );
+        stakeETHTally += requiredETH;
+
         // Convert required ETH from WETH
         IWETH9(WETH_TOKEN_ADDRESS).withdraw(requiredETH);
         _wethWithdrawnAndStaked(requiredETH);

contracts/deploy/mainnet/000_mock.js

@@ -136,6 +136,11 @@ const deployMocks = async ({ getNamedAccounts, deployments }) => {
     from: deployerAddr,
   });
 
+  // Mock SSV Network
+  await deploy("MockDepositContract", {
+    from: deployerAddr,
+  });
+
   const dai = await ethers.getContract("MockDAI");
   const usdc = await ethers.getContract("MockUSDC");
   const usdt = await ethers.getContract("MockUSDT");
@@ -425,10 +430,6 @@ const deployMocks = async ({ getNamedAccounts, deployments }) => {
     from: deployerAddr,
   });
 
-  await deploy("BeaconChainDepositContractMock", {
-    from: deployerAddr,
-  });
-
   console.log("000_mock deploy done.");
 
   return true;

contracts/deploy/mainnet/097_native_ssv_staking.js

@@ -195,7 +195,20 @@ module.exports = deploymentWithGovernanceProposal(
           signature: "setRegistrator(address)",
           args: [addresses.mainnet.validatorRegistrator],
         },
-        // 6. Upgrade the OETH Harvester
+        // 6. set staking threshold
+        {
+          contract: cStrategy,
+          signature: "setStakeETHThreshold(uint256)",
+          // TODO: confirm this number makes sense
+          args: [ethers.utils.parseEther("32")], // 32ETH * 32
+        },
+        // 7. set staking monitor
+        {
+          contract: cStrategy,
+          signature: "setStakingMonitor(address)",
+          args: [addresses.mainnet.Guardian], // 32ETH * 32
+        },
+        // 8. Upgrade the OETH Harvester
         {
           contract: cOETHHarvesterProxy,
           signature: "upgradeTo(address)",

contracts/test/_fixture.js

@@ -1617,6 +1617,7 @@ async function nativeStakingSSVStrategyFixture() {
       addresses.mainnet.SSVNetwork
     );
   } else {
+    fixture.ssvNetwork = await ethers.getContract("MockSSVNetwork");
     const { governorAddr } = await getNamedAccounts();
     const { oethVault, weth, nativeStakingSSVStrategy } = fixture;
     const sGovernor = await ethers.provider.getSigner(governorAddr);
@@ -1641,6 +1642,8 @@ async function nativeStakingSSVStrategyFixture() {
     await nativeStakingSSVStrategy
       .connect(sGovernor)
       .setRegistrator(governorAddr);
+
+    fixture.validatorRegistrator = sGovernor;
   }
 
   return fixture;

contracts/test/behaviour/ssvStrategy.js

@@ -82,6 +82,10 @@ const shouldBehaveLikeAnSsvStrategy = (context) => {
         addresses.validatorRegistrator,
         "Incorrect validator registrator"
       );
+      await expect(await nativeStakingSSVStrategy.stakingMonitor()).to.equal(
+        addresses.Guardian,
+        "Incorrect validator registrator"
+      );
     });
   });
 

contracts/test/helpers.js

@@ -489,9 +489,8 @@ const getAssetAddresses = async (deployments) => {
       BAL: (await deployments.get("MockBAL")).address,
       SSV: (await deployments.get("MockSSV")).address,
       SSVNetwork: (await deployments.get("MockSSVNetwork")).address,
-      beaconChainDepositContract: (
-        await deployments.get("BeaconChainDepositContractMock")
-      ).address,
+      beaconChainDepositContract: (await deployments.get("MockDepositContract"))
+        .address,
     };
 
     try {